Suction motors



w. E. OSHE I sucnou MOTORS Filed Feb. 21. 1955 July 9, 1957 Inventor William E. O'Jhei United States PatentO SUCTION MOTORS William Edward OShei, London, England Application February 21, 1955, Serial No. 489,433

Claims priority, application Great Britain February 24, 1954 6 Claims. (Cl. 121-464) The present invention relates to suction motors, and more particularly to suction motors of the oscillating paddle type as used for driving vehicle windscreen wipers.

An object of the invention is to provide a suction motor which will operate and provide adequate power for driving a windscreen wiper blade on lower degrees of vacuum than existing suction motors. Motors constructed as hereinafter described will, in fact, operate on very low vacuums, such as /2 inch of mercury or less. It is, of course, necessary, in order to provide a suction motor which will operate on low degrees of vacuum, to reduce as much as possible the friction between the moving parts, particularly between the oscillating paddle and the paddle chamber in which it moves, whilst reducing as much as possible leakage past the paddle. This alone, however, is not sutiicient to enable the motor to operate on very low degrees of vacuum. I have found that another important factor concerns the size of the valve ports and pass-ages in the motor through which the fluid has t-oflow, and that by increasing the size of these ports and passages the friction to fluid flow through the passages "can be reduced so that even very low degrees ofvacuum can successfully operate the motor.

The present invention provides a construction which enables the size of the ports and passages to be increased to improve the motor operation without, however, having to increase to any substantial extent the overall dimensions of the motor. In other words, thede sign of an existing suction motor of any particular size can, after modification in accordance with this invention, result in the manufacture of a motor of substantially the same size but considerably increased power on low vacuum.

According to one feature of the invention, the ports associated with the semi-rotary automatic valve are increased in area by making them elongated in radial directions relative to the axis about which the valve swings. In this way the spacing between the ports requisite for the prevention of leakage therebetween can be maintained, and it is only necessary to increase the width of the slot in the valve to correspond with the increased radial length of the ports in order to achieve the increased passageway necessary for achieving the results of this invention. Preferably the ports are made rectangular or of a trapezoidal shape in order to obtain the maximum port areas.

The passages leading from the ports to opposite sides of the paddle chamber are made of correspondingly increased size and of minimum length. With existing motor constructions, the manual control valve for starting, stopping and parking the motor is generally arranged on the cover of the motor housing to one side of the centre line of the motor and according to another feature of this invention the manual control valve is arranged substantially in the centre of the cover and directly above the ports of the automatic valve mechanism whereby the passages leading between these ports and the opposite ends of the motor, via the manual control valve, maybe of minimum and substantially equal length, thereby :not only reducing fluid friction in the passages but also re- "ice ducing limping which results from the passages between the automatic valve and opposite ends of the motor being of unequal lengths.

According to a further feature of the invention, the manual control valve is constructed as a semi-rotary valve movable between limits over a flat seating arranged in the centre of the cover. The valve seating may be surrounded by a cylindrical wall within which the semirotary valve, of circular shape, may be turned, the underside of the valve, which is preferably made of a flexible material such as synthetic rubber, being provided with passages for interconnecting the ports in its seating to efitect the starting and stopping of the motor, and for applying suction continuously to one side of the motor and atmosphere to the other side when the valve is in the stop position, whereby the paddle will be parked atone end of its stroke.

The size of the passages in the underside of the valve :are made of a size corresponding to the sizes of the other ports and passages so as to minimize the restriction of fluid flow.

According to a further feature of the invention, the manual valve is shaped so that by moving it to either of two alternative stop positions the motor can be selectively parked at either one end or the other of its limits of movement. The manual valve is actuated by a member which interlocks with the upper surface thereof and has an operating finger projecting radially therefrom outside the cylindrical wall defining the manual valve seating. Two pairs of spaced stops are provided which are preferably formed by cutting two slots in the top edge of the cylindrical wall, for limiting the movement of the finger projecting from the valve operating member, the finger being so arranged on the valve operating member that by inverting this member and changing the pairs of stops between which it is located, the manual valve will be movable selectively between the on position and be- .tween one or other of the stop and parking positions.

One embodiment according to the invention is illus- .trated in the accompanying drawings, in which:

Figure 1 shows a side view of the motor with the valve cover removed.

Figure 2 shows a .detail view of the automatic valve seat with the automatic valve removed.

Figure 3 shows a perspective view of the automatic valve from its inner side.

Figure 4 shows an exploded perspective View of the parts of the manual control valve and its seating.

Figure .5 shows a perspective view of the underside of the manual control valve.

:Referring to the drawing, the motor is of the conventional type having a paddle 26 movable in the paddle chamber 1 and actuating an automatic valve 2 through the medium of the kicker 3 actuated by the over-centre spring -4. The motor paddle is preferably constructed as described in my Patent No. 2,612,875 dated October 7 l952in order to provide minimum friction and leakage.

As shown in Figure 2, the ports 5a, 5b, 5c in the automatic valve seat are elongated in directions radially of the seating so as to be of trapezoidal form. By reason of the increased size of these ports, the valve 2 will be sucked more firmly on the valve seating than in conventional motors, and in order positively to ensure reversal of the valve at each stroke, the kicker member may be weighted and operates the valve with a hammer action as described in British Patent No. 691,483.

The ports '5a, 5b, 50 lead through large diameter passages to ports 10a, 10b, respectively on the circular valve seating 11 of the manual control valve 12 arranged at the centre of the cover 1a of the motor housing. .The valve seating 11 is surrounded by a cylindrical wall 13 which locates and guides the movement of the circular valve 12. The ports 10a, 10b, 100 are arranged on a circle close to the wall 13, on which circle are also arranged two further ports 10d, 105 leading respectively to opposite sides of the motor chamber 1. The port. 10d is arranged to be diametrically opposite the mid-point between the ports 10a and 10b and the port 106 is diametrically opposite the mid-point between the ports 10a and NC.

The connector 14 for connecting the motor to the source of suction leads to a port 15 on the valve seating 11 within the circle on which are located the ports 10; the valve seating 11 is also provided with a vent opening 16 leading to the atmosphere through the hole 19.

The valve 12 is preferably moulded of synthetic rubber material with two arcuate passages 12a therein and a centre annular passage 12]) connected with radial extensions 12c, 12d as shown in Figure 5. When the valve is in the position with the extension 120 over-lying the port 10a, the source of suction will be connected through the port 15 and the passage 12b and extension 120 to the automatic valve, and the ports 10b, 100 connected to opposite sides of the automatic valve will be connected by t'hearcuate passages 12a, to the ports 102 and 10d respectively. The motor will thus operate. The vent opening 16 is sealed off by the underside of the valve 12.

When the manual valve 12 is turned so that the extension 12c lies intermediate a pair of ports 10a and 10b or 10a and 100, the source of suction will be discnnected from the automatic valve and will be applied through the extension 12d to one or other of the ports 10d or 100 so as to park the motor at one end or the other. The other one of the ports 10a or 10d which is not connected to the source of suction will be connected to atmosphere through its associated arcuate passage 12a and the vent opening 16.

For actuating the manual control valve there is provided a disc-like actuating member 17 formed with cut-out portions corresponding to embossments on the upper surface of the valve 12. The parts are held in assembled relation by securing the cover plate 18 by means of the screw 23 which screws into the threaded aperture 25 in the valve seating 11. The actuating member 17 is moved by the finger 20 which extends through a slot 21 cut in the top edge of the cylindrical wall 13 surrounding the valve seating 11. The valve 12 is then movable between limits defined by the ends of this slot 21, for example by the flexible cable 24. By inverting the actuating member, its finger 20 will extend through another slot 22 cut in the top edge of the wall 13 and the valve will be movable between two other limiting positions. Depending upon the orientation of the actuating member and the slot 21 or 22 through which the finger 20 passes, the motor can be adjusted for parking at either its right-hand or left-hand end.

The paddle 26 is provided in known manner .with sealing members 27a, 27b, on opposite sides thereof which are respectively adapted in the respective parking positions of the paddle, to seal over the sealing caps 28a, 28b on the underside of the cover of the motor housing through which the passages leading from the ports 10a, 10a respectively connect with the interior of the motor chamber 1, and thereby seal off the supply of suction from the interior of the motor chamber when the paddle is in a parking position.

In one particular embodiment of the invention, applied to a motor having a paddle about 1.63 wide and swinging in a chamberof about 2.75" radius, the ports were made 0.195" long, in the radial direction, with their inner edges on an arc of 0.187" radius. The ports each extended for anarc of 24 with walls extending for arcs of 24 between the ports. The ports and and the passages leading therefrom were drilled 0.156" diameter.

Whilst a particular embodiment has been described, it will be understood that various modifications may be made without departing from the scope of this invention.

Thus the invention is not limited to suction motors of the oscillating paddle type; the novel automatic valve seating arrangement herein described can be applied to suction motors having reciprocating pistons or flexible diaphragms for producing motor movement.

I claim:

1. A suction motor in which a piston element is reciprocated by alternately applying suction to opposite sides of the piston element by means of an automatic reversing valve mechanism which simultaneously vents that side of the piston element to which suction is not applied, wherein the automatic reversing valve mecha nism comprises a semi-rotary valve movable about an axis, means for automatically moving said valve back and forth in accordance with the movement of the piston element, a valve seating over which said valve moves, three ports in said valve seating and arranged in an are about said axis, said ports each having a length in a direction radial to said axis which is greater than its width transverse to said radial direction, said valve having a recess in its face which cooperates with the ports, which recess has a width in said radial direction approximately equal to the length of the ports in said radial direction and extends for an are such that said recess is adapted to connect the central port alternately to the outer ports, said valve also venting to atmosphere the outer port which is not connected to the central port, a passage for connecting said central port to a source of suction, and further passages connecting said outer ports respectively to opposite sides of said piston element, said ports and said further passages having cross-sectional areas which are greater than the area of a circle having a diameter equal to the minimum spacing between two adjacent ports.

2. A suction motor as claimed in claim 1, wherein the cross-sectional area of said elongated ports is greater than the cross-sectional area of said further passages.

3. A suction motor comprising an arcuate motor chamber closed by a cover, a paddle mounted for oscillating movement in said chamber about an axis at the centre of said chamber, a semi-rotary valve movable about said axis and means for automatically moving said valve back and forth in accordance with the movement of said paddle, a valve seating over which said valve moves, three ports in said valve seating and arranged in an arc about said axis, said ports each having a length in a direction radial to said axis which is greater than its width transverse to said radial direction, said valve having a recess in its face which cooperates with the ports, which recess has a width in said radial direction approximately equal to the length of the ports in said radial direction and extends for an are such that said recess is adapted to connect the central port alternately to the outer ports, said valve also venting to atmosphere the outer port which is not connected to the central port, a passage for connecting said central port to a source of suction, and further passages connecting said outer ports respectively to the motor chamber at opposite sides of said paddle, said further passages having cross-sectional areas which are greater than the area of a circle having a diameter equal to the minimum spacing between two adjacent ports, and the areas of said elongated ports being not less than the crosssectional areas of said further passages.

4. A suction motor comprising an arcuate motor chamber closed .by a cover, a paddle mounted for oscillating movement in said chamber about an axis at the centre of said chamber, a semi-rotary valve movable about said axis and means for automatically moving said valve back and forth in accordance with the movement of said paddle, a valve seating over which said valve moves, three ports in said valve seating and arranged in an arc not exceed ing about about said axis, said ports being of trapezoidal shape and each extending for about 24 around said arc, and being spaced by about 24, the minimum spacing between adjacent ports being not less than and the radial length of a port being about 7 said valve having a recess in its face which cooperates with the ports, which recess has a width in said radial direction of about 2 and extends for an arc of approximately 72 whereby said recess is adapted to connect the central port alternately to the outer ports, said valve also venting to atmosphere the outer port which is not connected to the central port, a passage for connecting said central port to a source of suction, and further passages connecting said outer ports respectively to the motor chamber at opposite sides of said paddle, said further passages having a cross-sectional area which is greater than the area of a circle having a diameter equal to the mean spacing between two adjacent ports.

5. A suction motor comprising an arcuate motor chamber closed by a cover, a paddle mounted for oscillating movement in said chamber about an axis at the centre of said chamber, a semi-rotary valve movable about said axis and means for automatically moving said valve back and forth in accordance with the movement of said paddle, a valve seating over which said valve moves, three ports in said valve seating and arranged in an arc not exceeding about 120 about said axis, said ports being of trapezoidal shape and each extending for about 24 around said arc, and being spaced by about 24, the inner edges of the ports lying on a radius of about about said axis and said ports having a radial length of about said valve having a recess in its face which cooperates with the ports, which recess has a width in said radial direction of about 71 and extends for an arc of approximately 72 whereby said recess is adapted to connect the central port alternately to the outer ports, said valve also venting to atmosphere the outer port which is not connected to the central port, a passage for connecting said central port to a source of suction, and further passages connecting said outer ports respectively to the motor chamber at opposite sides of said paddle, said further passages having a cross-sectional area which is not less than the area of a circle having a diameter of 6. A suction motor in which a piston element is reciprocated by alternately applying suction to opposite sides of the piston element by means of an automatic reversing valve mechanism which simultaneously vents that side of the piston element to which suction is not applied, wherein the automatic reversing valve mechanism comprises a semi-rotary valve movable about an axis, means for automatically moving said valve back and forth in accordance with the movement of the piston element, a valve seating over which said valve moves, three ports in said valve seating and arranged in an are not exceeding about said axis, said ports being of trapezoidal shape and each extending for about 24 around said arc, and being spaced about 24, the inner edges of the ports lying on a radius of about around said axis and said ports and having a radial length of about A said valve having a recess in its face which cooperates with the ports, which recess has a width in said radial direction of about W and extends for an arc of approximately 72 whereby said recess is adapted to connect the central port alternately to the outer ports, said valve also venting to atmosphere the outer port which is not connected to the central port, a passage for connecting said central port to a source of suction, and further passages connecting said outer ports respectively to the motor chamber at opposite sides of said paddle.

References Cited in the file of this patent UNITED STATES PATENTS 1,738,311 Oishei et a1. Dec. 3, 1929 1,826,461 Davis Oct. 6, 1931 2,563,068 Rappl Aug. 7, 1951 2,590,475 Stoltenberg Mar. 25, 1952 2,670,718 Tomlin Mar. 2, 1.954 2,696,805 Krohm Dec. 14, 1954 2,698,607 Krohm Jan. 4, 1955 FOREIGN PATENTS 484,349 Canada June 24, 1952 

